One Self
The true person is not anyone in particular. But like the deep blue colour of the limitless sky, it is everyone, everywhere in the world.
Dogen.
You may understand how it is possible that the vision of a countless number of men and other animals that are gifted with sight can at one and the same time be directed upon a single visible object. For instance, a little golden ball placed upon the topmost pinnacle of a tower is simultaneously visible to all that stand about it in any direction, and each one of the beholders fixes upon it the rays of his sight, and no one says to another, Remove your sight so that I may see what you are looking at: for all may see at once. If then so many rays may flow together into one, without any confusion or mixture or composition between them, for each one of the observers retains his own proper sight so that all are by a wonderful unification directed upon one and the same object: why should not all men be restored into some mystical unity, although each retains unimpaired the properties of his body, his soul and his Mind.
Erigena
Knowing that thy Self is the Self of all beings and that all beings abide in the Self, released from egoity and the sense of mine and thine, live in bliss.
Ashtavakra Gita
Within each of us is a point where all of us meet. And within that point is a place where we are all one simple essence. That is the soul of the Messiah within us.
Rabbi Menachem Mendel Schneerson (paraphrased by Rabbi Tzvi Freeman)
Hear O Israel, the Lord our God is One Lord. The Book of Deuteronomy, Old Testament.
When we look outside of that on which we depend we ignore our unity; looking outward we see many faces; look inward and all is one head. If a man could but be turned about, he would see at once God and himself and the All. Plotinus